How to make a linux Xorg based os recognize or use multiple screens without a graphic card?

kikoko · Wednesday at 06:55

Right now I am runing a server without a graphic card yet I can use lightdm/xfce4

I am going to refer to wiki of proxmox itself to show how useless these explanations are:

Display

QEMU can virtualize a few types of VGA hardware. Some examples are:

std, the default, emulates a card with Bochs VBE extensions.
cirrus, this was once the default, it emulates a very old hardware module with all its problems. This display type should only be used if really necessary [10], for example, if using Windows XP or earlier
vmware, is a VMWare SVGA-II compatible adapter.
qxl, is the QXL paravirtualized graphics card. Selecting this also enables SPICE (a remote viewer protocol) for the VM.

virtio-gl, often named VirGL is a virtual 3D GPU for use inside VMs that can offload workloads to the host GPU without requiring special (expensive) models and drivers and neither binding the host GPU completely, allowing reuse between multiple guests and or the host.

VirGL support needs some extra libraries that aren’t installed by default due to being relatively big and also not available as open source for all GPU models/vendors. For most setups you’ll just need to do: apt install libgl1 libegl1

You can edit the amount of memory given to the virtual GPU, by setting the memory option. This can enable higher resolutions inside the VM, especially with SPICE/QXL.
As the memory is reserved by display device, selecting Multi-Monitor mode for SPICE (such as qxl2 for dual monitors) has some implications:

Windows needs a device for each monitor, so if your ostype is some version of Windows, Proxmox VE gives the VM an extra device per monitor. Each device gets the specified amount of memory.
Linux VMs, can always enable more virtual monitors, but selecting a Multi-Monitor mode multiplies the memory given to the device with the number of monitors.

Selecting serialX as display type disables the VGA output, and redirects the Web Console to the selected serial port. A configured display memory setting will be ignored in that case.

> Linux VMs, can always enable more virtual monitors, but selectinga Multi-Monitor mode multiplies the memory given to the device withthe number of monitors.

Now let's see the difference in output between qxl4 and the default one i am using (virtio-gpu)

qxl4:
```
lspci
00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02)
00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
00:01.2 USB controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01)
00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
00:02.0 VGA compatible controller: Red Hat, Inc. QXL paravirtual graphic card (rev 05)
00:03.0 Unclassified device [00ff]: Red Hat, Inc. Virtio memory balloon
00:05.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
00:08.0 Communication controller: Red Hat, Inc. Virtio console
00:09.0 Communication controller: Red Hat, Inc. Virtio console
00:12.0 Ethernet controller: Red Hat, Inc. Virtio network device
00:1e.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
00:1f.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
01:01.0 SCSI storage controller: Red Hat, Inc. Virtio SCSI
03:0c.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
root@debian:~/Desktop# xrandr --listmonitors
Monitors: 1
0: +Virtual-1 1920/508x1080/286+0+0 Virtual-1
```

and virtio

```
lspci
00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02)
00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
00:01.2 USB controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01)
00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
00:02.0 VGA compatible controller: Red Hat, Inc. Virtio 1.0 GPU (rev 01)
00:03.0 Unclassified device [00ff]: Red Hat, Inc. Virtio memory balloon
00:05.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
00:08.0 Communication controller: Red Hat, Inc. Virtio console
00:09.0 Communication controller: Red Hat, Inc. Virtio console
00:12.0 Ethernet controller: Red Hat, Inc. Virtio network device
00:1e.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
00:1f.0 PCI bridge: Red Hat, Inc. QEMU PCI-PCI bridge
01:01.0 SCSI storage controller: Red Hat, Inc. Virtio SCSI
03:0c.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
root@debian:~/Desktop# xrandr --listmonitors
Monitors: 1
0: +Virtual-1 1920/325x1080/203+0+0 Virtual-1

```

so the question
how does one add extra virtual monitor/screen whatever in linux environment if there's only one exposed vga interface? this question has never been answered on this forum, i checked every topic that mentions virtual screens for linux mentions, I don't need to connect to the vm right away, i just need it at least to get displayed in xrandr

kikoko · Wednesday at 07:02

@alex-fl

ness1602 · Wednesday at 08:19

Virtual screens are usually created in the background with tigervnc server or xvfb ,depending on use-case

kikoko · Wednesday at 11:25

well my current issue is the fact that in xorg i see logs saying virtual 1 screen detected and virtual 2-4 there's no screen/monitor for it so it gets disconnected, i don't need like a new export DISPLAY=:1, i just need the same export DISPLAY=:0 have the same lightdm running and have the same xfce session, just 2 screens basically

kikoko · Wednesday at 11:30

pay attention to where it says disconnected and has no monitor section

Code:

[     4.475]
X.Org X Server 1.21.1.16
X Protocol Version 11, Revision 0
[     4.475] Current Operating System: Linux debian 6.12.21-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.21-1 (2025-03-30) x86_64
[     4.475] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.12.21-amd64 root=UUID=3ef3a977-059a-4e81-a74e-c39d28be7b84 ro quiet
[     4.475] xorg-server 2:21.1.16-1 (https://www.debian.org/support)
[     4.475] Current version of pixman: 0.44.0
[     4.475]     Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.
[     4.475] Markers: (--) probed, (**) from config file, (==) default setting,
    (++) from command line, (!!) notice, (II) informational,
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[     4.475] (==) Log file: "/var/log/Xorg.0.log", Time: Wed Apr  2 09:27:07 2025
[     4.477] (==) Using config file: "/etc/X11/xorg.conf"
[     4.477] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[     4.479] (==) ServerLayout "X.org Configured"
[     4.479] (**) |-->Screen "Screen0" (0)
[     4.479] (**) |   |-->Monitor "Monitor0"
[     4.481] (**) |   |-->Device "Card0"
[     4.481] (**) |-->Input Device "Mouse0"
[     4.481] (**) |-->Input Device "Keyboard0"
[     4.481] (**) Allowing byte-swapped clients
[     4.481] (==) Automatically adding devices
[     4.481] (==) Automatically enabling devices
[     4.481] (==) Automatically adding GPU devices
[     4.481] (==) Automatically binding GPU devices
[     4.481] (==) Max clients allowed: 256, resource mask: 0x1fffff
[     4.482] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[     4.482]     Entry deleted from font path.
[     4.485] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[     4.485]     Entry deleted from font path.
[     4.485] (**) FontPath set to:
    /usr/share/fonts/X11/misc,
    /usr/share/fonts/X11/100dpi/:unscaled,
    /usr/share/fonts/X11/75dpi/:unscaled,
    /usr/share/fonts/X11/Type1,
    /usr/share/fonts/X11/100dpi,
    /usr/share/fonts/X11/75dpi,
    built-ins,
    /usr/share/fonts/X11/misc,
    /usr/share/fonts/X11/100dpi/:unscaled,
    /usr/share/fonts/X11/75dpi/:unscaled,
    /usr/share/fonts/X11/Type1,
    /usr/share/fonts/X11/100dpi,
    /usr/share/fonts/X11/75dpi,
    built-ins
[     4.485] (**) ModulePath set to "/usr/lib/xorg/modules"
[     4.485] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[     4.485] (WW) Disabling Mouse0
[     4.485] (WW) Disabling Keyboard0
[     4.485] (II) Loader magic: 0x55f8f50fcf00
[     4.485] (II) Module ABI versions:
[     4.485]     X.Org ANSI C Emulation: 0.4
[     4.485]     X.Org Video Driver: 25.2
[     4.485]     X.Org XInput driver : 24.4
[     4.485]     X.Org Server Extension : 10.0
[     4.486] (++) using VT number 7

[     4.486] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[     4.487] (II) xfree86: Adding drm device (/dev/dri/card0)
[     4.487] (II) Platform probe for /sys/devices/pci0000:00/0000:00:02.0/drm/card0
[     4.495] (--) PCI:*(0@0:2:0) 1b36:0100:1af4:1100 rev 5, Mem @ 0xf0000000/134217728, 0xf8000000/67108864, 0xfc650000/8192, I/O @ 0x0000f0e0/32, BIOS @ 0x????????/131072
[     4.495] (II) "glx" will be loaded. This was enabled by default and also specified in the config file.
[     4.495] (II) LoadModule: "glx"
[     4.497] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[     4.510] (II) Module glx: vendor="X.Org Foundation"
[     4.510]     compiled for 1.21.1.16, module version = 1.0.0
[     4.510]     ABI class: X.Org Server Extension, version 10.0
[     4.510] (II) LoadModule: "qxl"
[     4.510] (II) Loading /usr/lib/xorg/modules/drivers/qxl_drv.so
[     4.514] (II) Module qxl: vendor="X.Org Foundation"
[     4.514]     compiled for 1.21.1.15, module version = 0.1.6
[     4.514]     Module class: X.Org Video Driver
[     4.514]     ABI class: X.Org Video Driver, version 25.2
[     4.514] (II) qxl: Driver for QXL virtual graphics: QXL 1
[     4.516] (II) [KMS] Kernel modesetting enabled.
[     4.517] (==) qxl(0): Depth 24, (--) framebuffer bpp 32
[     4.517] (==) qxl(0): RGB weight 888
[     4.517] (==) qxl(0): Default visual is TrueColor
[     4.517] (==) qxl(0): Using gamma correction (1.0, 1.0, 1.0)
[     4.517] (**) qxl(0): Option "NumHeads" "5"
[     4.517] (II) qxl(0): Deferred Frames: Disabled
[     4.517] (II) qxl(0): Offscreen Surfaces: Disabled
[     4.517] (II) qxl(0): Image Cache: Disabled
[     4.517] (II) qxl(0): Fallback Cache: Disabled
[     4.517] (==) qxl(0): DPI set to (96, 96)
[     4.517] (II) Loading sub module "fb"
[     4.517] (II) LoadModule: "fb"
[     4.517] (II) Module "fb" already built-in
[     4.517] (II) Loading sub module "ramdac"
[     4.517] (II) LoadModule: "ramdac"
[     4.517] (II) Module "ramdac" already built-in
[     4.518] (II) qxl(0): Output Virtual-1 using monitor section Monitor0
[     4.518] (II) qxl(0): Output Virtual-2 has no monitor section
[     4.518] (II) qxl(0): Output Virtual-3 has no monitor section
[     4.518] (II) qxl(0): Output Virtual-4 has no monitor section
[     4.519] (II) qxl(0): EDID for output Virtual-1
[     4.519] (II) qxl(0): Printing probed modes for output Virtual-1
[     4.519] (II) qxl(0): Modeline "1024x768"x60.0   65.00  1024 1048 1184 1344  768 771 777 806 -hsync -vsync (48.4 kHz eP)
[     4.519] (II) qxl(0): Modeline "2560x1600"x60.0  348.50  2560 2752 3032 3504  1600 1603 1609 1658 -hsync +vsync (99.5 kHz e)
[     4.519] (II) qxl(0): Modeline "2560x1600"x60.0  268.50  2560 2608 2640 2720  1600 1603 1609 1646 +hsync -vsync (98.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1920x1440"x60.0  234.00  1920 2048 2256 2600  1440 1441 1444 1500 -hsync +vsync (90.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1856x1392"x60.0  218.25  1856 1952 2176 2528  1392 1393 1396 1439 -hsync +vsync (86.3 kHz e)
[     4.519] (II) qxl(0): Modeline "1792x1344"x60.0  204.75  1792 1920 2120 2448  1344 1345 1348 1394 -hsync +vsync (83.6 kHz e)
[     4.519] (II) qxl(0): Modeline "2048x1152"x60.0  162.00  2048 2074 2154 2250  1152 1153 1156 1200 +hsync +vsync (72.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1920x1200"x59.9  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync (74.6 kHz e)
[     4.519] (II) qxl(0): Modeline "1920x1200"x60.0  154.00  1920 1968 2000 2080  1200 1203 1209 1235 +hsync -vsync (74.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1920x1080"x60.0  148.50  1920 2008 2052 2200  1080 1084 1089 1125 -hsync -vsync (67.5 kHz e)
[     4.519] (II) qxl(0): Modeline "1600x1200"x60.0  162.00  1600 1664 1856 2160  1200 1201 1204 1250 +hsync +vsync (75.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1680x1050"x60.0  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync (65.3 kHz e)
[     4.519] (II) qxl(0): Modeline "1680x1050"x59.9  119.00  1680 1728 1760 1840  1050 1053 1059 1080 +hsync -vsync (64.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1400x1050"x60.0  121.75  1400 1488 1632 1864  1050 1053 1057 1089 -hsync +vsync (65.3 kHz e)
[     4.519] (II) qxl(0): Modeline "1400x1050"x59.9  101.00  1400 1448 1480 1560  1050 1053 1057 1080 +hsync -vsync (64.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1600x900"x60.0  108.00  1600 1624 1704 1800  900 901 904 1000 +hsync +vsync (60.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x1024"x60.0  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1440x900"x59.9  106.50  1440 1520 1672 1904  900 903 909 934 -hsync +vsync (55.9 kHz e)
[     4.519] (II) qxl(0): Modeline "1440x900"x59.9   88.75  1440 1488 1520 1600  900 903 909 926 +hsync -vsync (55.5 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x960"x60.0  108.00  1280 1376 1488 1800  960 961 964 1000 +hsync +vsync (60.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x854"x60.0   89.34  1280 1352 1480 1680  854 857 867 887 -hsync +vsync (53.2 kHz)
[     4.519] (II) qxl(0): Modeline "1366x768"x59.8   85.50  1366 1436 1579 1792  768 771 774 798 +hsync +vsync (47.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1366x768"x60.0   72.00  1366 1380 1436 1500  768 769 772 800 +hsync +vsync (48.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1360x768"x60.0   85.50  1360 1424 1536 1792  768 771 777 795 +hsync +vsync (47.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x800"x59.8   83.50  1280 1352 1480 1680  800 803 809 831 -hsync +vsync (49.7 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x800"x59.9   71.00  1280 1328 1360 1440  800 803 809 823 +hsync -vsync (49.3 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x768"x59.9   79.50  1280 1344 1472 1664  768 771 778 798 -hsync +vsync (47.8 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x768"x60.0   68.25  1280 1328 1360 1440  768 771 778 790 +hsync -vsync (47.4 kHz e)
[     4.519] (II) qxl(0): Modeline "1280x720"x60.0   74.25  1280 1390 1430 1650  720 725 730 750 +hsync +vsync (45.0 kHz e)
[     4.519] (II) qxl(0): Modeline "1152x768"x59.9   71.95  1152 1216 1328 1504  768 771 781 798 -hsync +vsync (47.8 kHz)
[     4.519] (II) qxl(0): Modeline "800x600"x60.3   40.00  800 840 968 1056  600 601 605 628 +hsync +vsync (37.9 kHz e)
[     4.519] (II) qxl(0): Modeline "800x600"x56.2   36.00  800 824 896 1024  600 601 603 625 +hsync +vsync (35.2 kHz e)
[     4.519] (II) qxl(0): Modeline "848x480"x60.0   33.75  848 864 976 1088  480 486 494 517 +hsync +vsync (31.0 kHz e)
[     4.519] (II) qxl(0): Modeline "720x480"x59.9   26.85  720 744 808 896  480 483 493 500 -hsync +vsync (30.0 kHz)
[     4.519] (II) qxl(0): Modeline "640x480"x59.9   25.18  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz e)
[     4.519] (II) qxl(0): EDID for output Virtual-2
[     4.519] (II) qxl(0): EDID for output Virtual-3
[     4.519] (II) qxl(0): EDID for output Virtual-4
[     4.519] (II) qxl(0): Output Virtual-1 connected
[     4.519] (II) qxl(0): Output Virtual-2 disconnected
[     4.519] (II) qxl(0): Output Virtual-3 disconnected
[     4.519] (II) qxl(0): Output Virtual-4 disconnected
[     4.519] (II) qxl(0): Using exact sizes for initial modes
[     4.519] (II) qxl(0): Output Virtual-1 using initial mode 1024x768 +0+0
[     4.519] (II) qxl(0): PreInit complete
[     4.523] (II) UXA(0): Driver registered support for the following operations:
[     4.523] (II)         solid
[     4.523] (II)         copy
[     4.523] (II)         composite (RENDER acceleration)
[     4.523] (II)         put_image
[     4.524] resizing primary to 1024x768
[     4.525] primary is 0x55f92a195670
[     4.528] (II) Initializing extension Generic Event Extension
[     4.528] (II) Initializing extension SHAPE
[     4.528] (II) Initializing extension MIT-SHM
[     4.528] (II) Initializing extension XInputExtension
[     4.529] (II) Initializing extension XTEST
[     4.529] (II) Initializing extension BIG-REQUESTS
[     4.529] (II) Initializing extension SYNC
[     4.529] (II) Initializing extension XKEYBOARD
[     4.529] (II) Initializing extension XC-MISC
[     4.529] (II) Initializing extension SECURITY
[     4.530] (II) Initializing extension XFIXES
[     4.530] (II) Initializing extension RENDER
[     4.530] (II) Initializing extension RANDR
[     4.530] (II) Initializing extension COMPOSITE
[     4.530] (II) Initializing extension DAMAGE
[     4.530] (II) Initializing extension MIT-SCREEN-SAVER
[     4.530] (II) Initializing extension DOUBLE-BUFFER
[     4.530] (II) Initializing extension RECORD
[     4.530] (II) Initializing extension DPMS
[     4.530] (II) Initializing extension Present
[     4.531] (II) Initializing extension DRI3
[     4.531] (II) Initializing extension X-Resource
[     4.531] (II) Initializing extension XVideo
[     4.531] (II) Initializing extension XVideo-MotionCompensation
[     4.531] (II) Initializing extension SELinux
[     4.531] (II) SELinux: Disabled on system
[     4.531] (II) Initializing extension GLX
[     4.531] (II) AIGLX: Screen 0 is not DRI2 capable
[     4.916] (II) IGLX: Loaded and initialized swrast
[     4.916] (II) GLX: Initialized DRISWRAST GL provider for screen 0
[     4.916] (II) Initializing extension XFree86-VidModeExtension
[     4.917] (II) Initializing extension XFree86-DGA
[     4.917] (II) Initializing extension XFree86-DRI
[     4.917] (II) Initializing extension DRI2
[     4.917] (II) qxl(0): Setting screen physical size to 270 x 203
[     5.003] (II) config/udev: Adding input device Power Button (/dev/input/event1)
[     5.003] (**) Power Button: Applying InputClass "libinput keyboard catchall"
[     5.003] (II) LoadModule: "libinput"
[     5.003] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[     5.009] (II) Module libinput: vendor="X.Org Foundation"
[     5.009]     compiled for 1.21.1.15, module version = 1.5.0
[     5.009]     Module class: X.Org XInput Driver
[     5.009]     ABI class: X.Org XInput driver, version 24.4
[     5.009] (II) Using input driver 'libinput' for 'Power Button'
[     5.009] (**) Power Button: always reports core events
[     5.009] (**) Option "Device" "/dev/input/event1"
[     5.024] (II) event1  - Power Button: is tagged by udev as: Keyboard
[     5.024] (II) event1  - Power Button: device is a keyboard
[     5.024] (II) event1  - Power Button: device removed
[     5.072] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input2/event1"
[     5.072] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 6)
[     5.072] (**) Option "xkb_model" "pc105"
[     5.072] (**) Option "xkb_layout" "us"
[     5.074] (II) event1  - Power Button: is tagged by udev as: Keyboard
[     5.074] (II) event1  - Power Button: device is a keyboard
[     5.075] (II) config/udev: Adding input device AT Translated Set 2 keyboard (/dev/input/event0)
[     5.076] (**) AT Translated Set 2 keyboard: Applying InputClass "libinput keyboard catchall"
[     5.076] (II) Using input driver 'libinput' for 'AT Translated Set 2 keyboard'
[     5.076] (**) AT Translated Set 2 keyboard: always reports core events
[     5.076] (**) Option "Device" "/dev/input/event0"
[     5.077] (II) event0  - AT Translated Set 2 keyboard: is tagged by udev as: Keyboard
[     5.077] (II) event0  - AT Translated Set 2 keyboard: device is a keyboard
[     5.078] (II) event0  - AT Translated Set 2 keyboard: device removed
[     5.128] (**) Option "config_info" "udev:/sys/devices/platform/i8042/serio0/input/input0/event0"

kikoko · Wednesday at 11:34

even if i remove xorg.conf it still says the same, i tried qxl4, qxl2, qxl3, qxl etc., nothing worked, same issue when i try adding some lowest possible screen resolution and fps (lets say 30) it just blinks for a second and obviously disconnects since there's no monitor i suppose

Code:

root@debian:~# xrandr --query
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
Virtual-1 connected 1920x1080+0+0 0mm x 0mm
   1024x768      60.00 +
   2560x1600     59.99    59.97 
   1920x1440     60.00 
   1856x1392     60.00 
   1792x1344     60.00 
   2048x1152     60.00 
   1920x1200     59.88    59.95 
   1920x1080     60.00*
   1600x1200     60.00 
   1680x1050     59.95    59.88 
   1400x1050     59.98    59.95 
   1600x900      60.00 
   1280x1024     60.02 
   1440x900      59.89    59.90 
   1280x960      60.00 
   1280x854      59.95 
   1366x768      59.79    60.00 
   1360x768      60.02 
   1280x800      59.81    59.91 
   1280x768      59.87    59.99 
   1280x720      60.00 
   1152x768      59.95 
   800x600       60.32    56.25 
   848x480       60.00 
   720x480       59.94 
   640x480       59.94 
Virtual-2 disconnected
Virtual-3 disconnected
Virtual-4 disconnected
root@debian:~# xrandr --output Virtual-2 --auto
root@debian:~# cvt 640 480 30
# 640x480 29.79 Hz (CVT) hsync: 14.69 kHz; pclk: 11.75 MHz
Modeline "640x480_30.00"   11.75  640 656 720 800  480 483 487 493 -hsync +vsync
root@debian:~# xrandr --newmode "640x480_30.00"   11.75  640 656 720 800  480 483 487 493 -hsync +vsync
root@debian:~# xrandr --addmode Virtual-2  "640x480_30.00"
root@debian:~# xrandr --output Virtual-2 --mode "640x480_30.00" --right-of Virtual-1
root@debian:~# xrandr --query
Screen 0: minimum 320 x 200, current 2560 x 1080, maximum 8192 x 8192
Virtual-1 connected 1920x1080+0+0 0mm x 0mm
   1024x768      60.00 +
   2560x1600     59.99    59.97 
   1920x1440     60.00 
   1856x1392     60.00 
   1792x1344     60.00 
   2048x1152     60.00 
   1920x1200     59.88    59.95 
   1920x1080     60.00*
   1600x1200     60.00 
   1680x1050     59.95    59.88 
   1400x1050     59.98    59.95 
   1600x900      60.00 
   1280x1024     60.02 
   1440x900      59.89    59.90 
   1280x960      60.00 
   1280x854      59.95 
   1366x768      59.79    60.00 
   1360x768      60.02 
   1280x800      59.81    59.91 
   1280x768      59.87    59.99 
   1280x720      60.00 
   1152x768      59.95 
   800x600       60.32    56.25 
   848x480       60.00 
   720x480       59.94 
   640x480       59.94 
Virtual-2 disconnected 640x480+1920+0 0mm x 0mm
   640x480_30.00  29.79*
Virtual-3 disconnected
Virtual-4 disconnected

i legit ran out of ideas at this point

kikoko · Wednesday at 11:35

my main concern is where are these "virtual-1" coming from even? I legit have no idea, there's no virtual-1 even in my xorg.conf, lol

```
grep -r "Virtual-" / 2>/dev/null
/sys/kernel/debug/dri/0000:00:02.0/state:connector[42]: Virtual-1
/sys/kernel/debug/dri/0000:00:02.0/state:connector[51]: Virtual-2
/sys/kernel/debug/dri/0000:00:02.0/state:connector[60]: Virtual-3
/sys/kernel/debug/dri/0000:00:02.0/state:connector[69]: Virtual-4
```

Code:

cat /sys/kernel/debug/dri/0/state
plane[35]: plane-0
    crtc=crtc-0
    fb=75
        allocated by = Xorg
        refcount=2
        format=XR24 little-endian (0x34325258)
        modifier=0x0
        size=1920x1080
        layers:
            size[0]=1920x1080
            pitch[0]=7680
            offset[0]=0
            obj[0]:
                name=0
                refcount=4
                start=00100d8e
                size=8302592
                imported=no
                placement=(none)
                bus.offset=f8304000
    crtc-pos=1920x1080+0+0
    src-pos=1920.000000x1080.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[37]: plane-1
    crtc=crtc-0
    fb=74
        allocated by = Xorg
        refcount=1
        format=AR24 little-endian (0x34325241)
        modifier=0x0
        size=64x64
        layers:
            size[0]=64x64
            pitch[0]=256
            offset[0]=0
            obj[0]:
                name=0
                refcount=2
                start=00103911
                size=16384
                imported=no
                placement=(none)
                bus.offset=0
    crtc-pos=64x64+549+742
    src-pos=64.000000x64.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[44]: plane-2
    crtc=(null)
    fb=0
    crtc-pos=640x480+0+0
    src-pos=640.000000x480.000000+1920.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[46]: plane-3
    crtc=(null)
    fb=0
    crtc-pos=0x0+0+0
    src-pos=0.000000x0.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[53]: plane-4
    crtc=(null)
    fb=0
    crtc-pos=0x0+0+0
    src-pos=0.000000x0.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[55]: plane-5
    crtc=(null)
    fb=0
    crtc-pos=0x0+0+0
    src-pos=0.000000x0.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[62]: plane-6
    crtc=(null)
    fb=0
    crtc-pos=0x0+0+0
    src-pos=0.000000x0.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
plane[64]: plane-7
    crtc=(null)
    fb=0
    crtc-pos=0x0+0+0
    src-pos=0.000000x0.000000+0.000000+0.000000
    rotation=1
    normalized-zpos=0
    color-encoding=ITU-R BT.601 YCbCr
    color-range=YCbCr limited range
    color_mgmt_changed=0
crtc[41]: crtc-0
    enable=1
    active=1
    self_refresh_active=0
    planes_changed=1
    mode_changed=0
    active_changed=0
    connectors_changed=0
    color_mgmt_changed=0
    plane_mask=3
    connector_mask=1
    encoder_mask=1
    mode: "": 60 148500 1920 2008 2052 2200 1080 1084 1089 1125 0x0 0xa
crtc[50]: crtc-1
    enable=1
    active=0
    self_refresh_active=0
    planes_changed=1
    mode_changed=0
    active_changed=0
    connectors_changed=0
    color_mgmt_changed=0
    plane_mask=0
    connector_mask=2
    encoder_mask=2
    mode: "": 30 11750 640 656 720 800 480 483 487 493 0x0 0x6
crtc[59]: crtc-2
    enable=0
    active=0
    self_refresh_active=0
    planes_changed=0
    mode_changed=0
    active_changed=0
    connectors_changed=0
    color_mgmt_changed=0
    plane_mask=0
    connector_mask=0
    encoder_mask=0
    mode: "": 0 0 0 0 0 0 0 0 0 0 0x0 0x0
crtc[68]: crtc-3
    enable=0
    active=0
    self_refresh_active=0
    planes_changed=0
    mode_changed=0
    active_changed=0
    connectors_changed=0
    color_mgmt_changed=0
    plane_mask=0
    connector_mask=0
    encoder_mask=0
    mode: "": 0 0 0 0 0 0 0 0 0 0 0x0 0x0
connector[42]: Virtual-1
    crtc=crtc-0
    self_refresh_aware=0
    max_requested_bpc=0
    colorspace=Default
connector[51]: Virtual-2
    crtc=crtc-1
    self_refresh_aware=0
    max_requested_bpc=0
    colorspace=Default
connector[60]: Virtual-3
    crtc=(null)
    self_refresh_aware=0
    max_requested_bpc=0
    colorspace=Default
connector[69]: Virtual-4
    crtc=(null)
    self_refresh_aware=0
    max_requested_bpc=0
    colorspace=Default

ness1602 · Wednesday at 11:43

Could it be that it is from ubuntu or whatever linux virtual workspaces?

kikoko · Wednesday at 11:46

ness1602 said:
Could it be that it is from ubuntu or whatever linux virtual workspaces?

i am using debian, but let me delete workspaces related packages and plugins, its qxl though, i doubt its any sort of workspace related thing

kikoko · Wednesday at 11:51

set number of workspaces to 1, removed all others, reboot, still same logs.

guruevi · Wednesday at 12:44

Have you clicked through to any of the documentation? If you’re using SPICE: https://www.spice-space.org/multiple-monitors.html
XRDP+Xorg support multiple monitors
TigerVNC supports multiple monitors

In Linux you don’t need an actual graphics card for the latter two, SPICE can do 4 monitors on 1 virtual card in Linux.

Now how to setup Xorg with multiple SPICE monitors is no longer a Proxmox related question but if I remember correctly, XSpice just listens to what the clients ask for and configures the displays accordingly.

kikoko · Wednesday at 18:49

guruevi said:
Have you clicked through to any of the documentation? If you’re using SPICE: https://www.spice-space.org/multiple-monitors.html

I said I am not using spice.

Also I've literally cited the documentation lol?

guruevi said:
TigerVNC supports multiple monitors

Everything supports multiple monitors with qxl, the problem is with qxl driver not spawning monitors for the 2, 3 and 4th devices. It only spawns one, which leads to later failure due to lack of monitor.

kikoko · Wednesday at 18:57

[ 4.518] (II) qxl(0): Output Virtual-1 using monitor section Monitor0 [ 4.518] (II) qxl(0): Output Virtual-2 has no monitor section [ 4.518] (II) qxl(0): Output Virtual-3 has no monitor section [ 4.518] (II) qxl(0): Output Virtual-4 has no monitor section

[ 4.519] (II) qxl(0): EDID for output Virtual-2 [ 4.519] (II) qxl(0): EDID for output Virtual-3 [ 4.519] (II) qxl(0): EDID for output Virtual-4 [ 4.519] (II) qxl(0): Output Virtual-1 connected [ 4.519] (II) qxl(0): Output Virtual-2 disconnected [ 4.519] (II) qxl(0): Output Virtual-3 disconnected [ 4.519] (II) qxl(0): Output Virtual-4 disconnected

guruevi · Wednesday at 19:43

So you clearly do not understand - QXL = SPICE. If you're not using SPICE, you don't need QXL, it's irrelevant from that point forward.

The QXL driver doesn't "spawn" a monitor, when the SPICE client demands a 2nd-4th monitor it will forward that request to XSpice which then launches the X session with 4 monitors. Similar for Windows, except Windows RDP needs a QXL interface per monitor, the software then handles whether your remote client wants 1..4 monitor.

The VGA interface it provides to the guest is only there for 'convenience' so even Windows not running the SPICE guest software can output "something" to a "common" piece of hardware.

If you're not using SPICE, don't bother with any VGA output, it won't be used anyway. Whether it's VNC or RDP, they each have their own way of handling multi-monitors, VNC does not natively support multiple monitors on a single session, TigerVNC or RealVNC all have their own 'way' of doing it (again, usually spawning X server with options depending on the client's request).

kikoko · Wednesday at 19:47

speaking of vnc:

Code:

xtigervncviewer 192.168.1.2:5902
xtigervncviewer 192.168.1.2:5901

apt update
apt install tigervnc-standalone-server tigervnc-tools
vncpasswd
mkdir -p ~/.vnc
vncpasswd
#  184  strace vncpasswd
echo -e "#!/bin/sh\n# export DISPLAY=:1\nunset SESSION_MANAGER\nunset DBUS_SESSION_BUS_ADDRESS\nexec startxfce4" > /root/.vnc/xstartup
tigervncserver :1 -localhost no -xstartup ~/.vnc/xstartup
tigervncserver :2 -localhost no -xstartup ~/.vnc/xstartup

cat ~/.config/tigervnc/debian.lan\:1.log
cat ~/.config/tigervnc/debian.lan\:2.log

this is not what i need, i need actual 2 monitors, no to connect independently to different sessions but 2 monitors next to each other, that's my issue with qxl that for some reason it can't create virtual monitors for the 2, 3 and 4 devices.

kikoko · Wednesday at 19:48

guruevi said:
The QXL driver doesn't "spawn" a monitor, when the SPICE client demands a 2nd-4th monitor it will forward that request to XSpice which then launches the X session with 4 monitors. Similar for Windows, except Windows RDP needs a QXL interface per monitor, the software then handles whether your remote client wants 1..4 monitor.

Okay, is it possible to force it to spawn that session with 4 monitors without connecting via spice client?

kikoko · Wednesday at 19:51

guruevi said:
If you're not using SPICE, you don't need QXL

What if

i pick this driver, is it possible to have multiple virtual monitors using this or not? Without using a spice client to connect. I just don't see where to specify max outputs for virtio gpu.

guruevi · Wednesday at 19:57

Yeah - https://nouveau.freedesktop.org/MultiMonitorDesktop.html - except that you will output not to a physical piece of hardware under "Device" but you can use the "dummy" device. Eventually you'll have to output to "some interface" your remote desktop system provides.

Hence why XRDP and TigerVNC spawn the X11 on their own with the requested number of displays when requested by a compatible client. VNC servers may simply stretch the resolution and cut it in half, maybe they use 2 stream... I don't know exactly, it's somewhere in the documentation.

Note that I didn't fiddle AT ALL with any Xorg settings - this is just plain Xorg on Ubuntu with XRDP, then in my RDP client I tell it to use "all my monitors". You can see it requested how I wanted "all my monitors" (sadly only 2) configured on the guest.

As per your previous question, you don't need a display attached to the VM at all to do this, leave it on Default. It's not using it for rendering anything other than the console. Unless you're using SPICE, VNC and RDP completely ignore that VGA card.

Hell, you don't even need to run Xorg on your console. I have containers that launch Xorg sessions and provide that session using noVNC to a web socket on a remote web application.

kikoko · Wednesday at 20:02

I'll try it out rn again bro, thanks, last time I tried with dummy driver it just didn't let me start lightdm it was mad annoying, just black screen/console session.

kikoko · Wednesday at 20:36

So I stopped lightdm, switched to another tty, typed X -configure and here's the config it gives me:

Code:

Section "ServerLayout"
    Identifier     "X.org Configured"
    Screen      0  "Screen0" 0 0
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
    ModulePath   "/usr/lib/xorg/modules"
    FontPath     "/usr/share/fonts/X11/misc"
    FontPath     "/usr/share/fonts/X11/cyrillic"
    FontPath     "/usr/share/fonts/X11/100dpi/:unscaled"
    FontPath     "/usr/share/fonts/X11/75dpi/:unscaled"
    FontPath     "/usr/share/fonts/X11/Type1"
    FontPath     "/usr/share/fonts/X11/100dpi"
    FontPath     "/usr/share/fonts/X11/75dpi"
    FontPath     "built-ins"
EndSection

Section "Module"
    Load  "glx"
EndSection

Section "InputDevice"
    Identifier  "Keyboard0"
    Driver      "kbd"
EndSection

Section "InputDevice"
    Identifier  "Mouse0"
    Driver      "mouse"
    Option        "Protocol" "auto"
    Option        "Device" "/dev/input/mice"
    Option        "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
EndSection

Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
        ### <percent>: "<f>%"
        ### [arg]: arg optional
        #Option     "SWcursor"               # [<bool>]
        #Option     "kmsdev"                 # <str>
        #Option     "ShadowFB"               # [<bool>]
        #Option     "AccelMethod"            # <str>
        #Option     "PageFlip"               # [<bool>]
        #Option     "ZaphodHeads"            # <str>
        #Option     "DoubleShadow"           # [<bool>]
        #Option     "Atomic"                 # [<bool>]
        #Option     "VariableRefresh"        # [<bool>]
        #Option     "UseGammaLUT"            # [<bool>]
        #Option     "AsyncFlipSecondaries"     # [<bool>]
    Identifier  "Card0"
    Driver      "modesetting"
    BusID       "PCI:0:2:0"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Card0"
    Monitor    "Monitor0"
    SubSection "Display"
        Viewport   0 0
        Depth     1
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     4
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     8
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     15
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     16
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

PCI:0:2:0 is because I am using virtio gpu as my display (should I switch to "default" in proxmox's vm settings? is that what you were implying?).

I run apt install xserver-xorg-video-dummy to get the driver installed obviously.

Then I modify the config (marked additions with # Test so you don't have to run through):

Code:

Section "ServerLayout"
    Identifier     "X.org Configured"
    Screen      0  "Screen0" 0 0
# Test
        Screen      1  "Screen1" RightOf "Screen0"
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"
    ModulePath   "/usr/lib/xorg/modules"
    FontPath     "/usr/share/fonts/X11/misc"
    FontPath     "/usr/share/fonts/X11/cyrillic"
    FontPath     "/usr/share/fonts/X11/100dpi/:unscaled"
    FontPath     "/usr/share/fonts/X11/75dpi/:unscaled"
    FontPath     "/usr/share/fonts/X11/Type1"
    FontPath     "/usr/share/fonts/X11/100dpi"
    FontPath     "/usr/share/fonts/X11/75dpi"
    FontPath     "built-ins"
EndSection

Section "Module"
        Load "dummy
    Load  "glx"
EndSection

Section "InputDevice"
    Identifier  "Keyboard0"
    Driver      "kbd"
EndSection

Section "InputDevice"
    Identifier  "Mouse0"
    Driver      "mouse"
    Option        "Protocol" "auto"
    Option        "Device" "/dev/input/mice"
    Option        "ZAxisMapping" "4 5 6 7"
EndSection

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "Monitor Model"
EndSection

Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
        ### <percent>: "<f>%"
        ### [arg]: arg optional
        #Option     "SWcursor"               # [<bool>]
        #Option     "kmsdev"                 # <str>
        #Option     "ShadowFB"               # [<bool>]
        #Option     "AccelMethod"            # <str>
        #Option     "PageFlip"               # [<bool>]
        #Option     "ZaphodHeads"            # <str>
        #Option     "DoubleShadow"           # [<bool>]
        #Option     "Atomic"                 # [<bool>]
        #Option     "VariableRefresh"        # [<bool>]
        #Option     "UseGammaLUT"            # [<bool>]
        #Option     "AsyncFlipSecondaries"     # [<bool>]
    Identifier  "Card0"
    Driver      "modesetting"
    BusID       "PCI:0:2:0"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device     "Card0"
    Monitor    "Monitor0"
    SubSection "Display"
        Viewport   0 0
        Depth     1
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     4
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     8
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     15
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     16
    EndSubSection
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

# Test
Section "Monitor"
    Identifier   "Monitor1"
    VendorName   "Dummy Vendor"
    ModelName    "Dummy Model"
    HorizSync 5.0 - 1000.0
    VertRefresh 5.0 - 200.0
    ModeLine "1920x1080" 148.50 1920 2448 2492 2640 1080 1084 1089 1125 +Hsync +Vsync
    # Option     "PreferredMode" "1920x1080"
EndSection

# Test
Section "Device"
    Identifier  "Card1"
    Driver      "dummy"
#    BusID       "PCI:0:2:1"
    Option      "Virtual"    "1920x1080"
    VideoRam 256000
EndSection

# Test
Section "Screen"
    Identifier "Screen1"
    Device     "Card1"
    Monitor    "Monitor1"
    DefaultDepth 24
    SubSection "Display"
        Viewport   0 0
        Depth      24
        Modes "1920x1080" "1280x800" "1024x768" "1920x1080" "1440x900"
    EndSubSection
EndSection

well first of all xrandr --query does not show the dummy monitor,

then there's bugs such as if i click somewhere let's say in X < 300 it works as expected, it clicks where I click, when I move mouse pointer to the right let's say X > 300, then it gets like a weird offset let's say 50 pixels

actual mouse click (X = 350) -------- WINDOW BUTTON (mouse click) (X = 400)

when i switch to 4k resolution there's no issue anymore.

So my question is, shall I switch from virtio gl to default and then simply create 2 dummy monitors or what?

the log
https://paste.js.org/dmiUlVjJH-rh

Code:

   796.032] (II) DUMMY(1): Output DUMMY0 using monitor section Monitor1
[   796.032] (II) DUMMY(1): Output DUMMY0 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791922b270) and output DUMMY0 (0x5579192d7660)
[   796.032] (II) DUMMY(1): Output DUMMY1 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919228fb0) and output DUMMY1 (0x55791add4ad0)
[   796.032] (II) DUMMY(1): Output DUMMY2 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791922f060) and output DUMMY2 (0x5579193008f0)
[   796.032] (II) DUMMY(1): Output DUMMY3 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919224670) and output DUMMY3 (0x55791930aaf0)
[   796.032] (II) DUMMY(1): Output DUMMY4 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919224b30) and output DUMMY4 (0x55791adc1720)
[   796.032] (II) DUMMY(1): Output DUMMY5 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791922f690) and output DUMMY5 (0x5579192213b0)
[   796.032] (II) DUMMY(1): Output DUMMY6 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919230160) and output DUMMY6 (0x55791adc1280)
[   796.032] (II) DUMMY(1): Output DUMMY7 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919230e90) and output DUMMY7 (0x557919231960)
[   796.032] (II) DUMMY(1): Output DUMMY8 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791923cdb0) and output DUMMY8 (0x55791922f520)
[   796.032] (II) DUMMY(1): Output DUMMY9 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791923d880) and output DUMMY9 (0x55791adc1ba0)
[   796.032] (II) DUMMY(1): Output DUMMY10 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791922d120) and output DUMMY10 (0x55791adc0d90)
[   796.032] (II) DUMMY(1): Output DUMMY11 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791ad0a4b0) and output DUMMY11 (0x55791adc08e0)
[   796.032] (II) DUMMY(1): Output DUMMY12 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791adc20c0) and output DUMMY12 (0x55791adc0430)
[   796.032] (II) DUMMY(1): Output DUMMY13 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x55791adc2ed0) and output DUMMY13 (0x55791922d920)
[   796.032] (II) DUMMY(1): Output DUMMY14 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919303da0) and output DUMMY14 (0x55791adc3750)
[   796.032] (II) DUMMY(1): Output DUMMY15 has no monitor section
[   796.032] (II) DUMMY(1): Created crtc (0x557919304bb0) and output DUMMY15 (0x55791adc3830)

[   796.034] (II) DUMMY(1): EDID for output DUMMY1
[   796.034] (II) DUMMY(1): EDID for output DUMMY2
[   796.034] (II) DUMMY(1): EDID for output DUMMY3
[   796.034] (II) DUMMY(1): EDID for output DUMMY4
[   796.034] (II) DUMMY(1): EDID for output DUMMY5
[   796.034] (II) DUMMY(1): EDID for output DUMMY6
[   796.034] (II) DUMMY(1): EDID for output DUMMY7
[   796.034] (II) DUMMY(1): EDID for output DUMMY8
[   796.034] (II) DUMMY(1): EDID for output DUMMY9
[   796.034] (II) DUMMY(1): EDID for output DUMMY10
[   796.034] (II) DUMMY(1): EDID for output DUMMY11
[   796.034] (II) DUMMY(1): EDID for output DUMMY12
[   796.034] (II) DUMMY(1): EDID for output DUMMY13
[   796.034] (II) DUMMY(1): EDID for output DUMMY14
[   796.034] (II) DUMMY(1): EDID for output DUMMY15
[   796.034] (II) DUMMY(1): Output DUMMY0 connected
[   796.034] (II) DUMMY(1): Output DUMMY1 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY2 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY3 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY4 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY5 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY6 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY7 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY8 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY9 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY10 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY11 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY12 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY13 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY14 disconnected
[   796.034] (II) DUMMY(1): Output DUMMY15 disconnected

Code:

[   796.034] (II) DUMMY(1): Using user preference for initial modes
[   796.034] (II) DUMMY(1): Output DUMMY0 using initial mode 1920x1080 +0+0

maybe i am using wrong viewport for it?

How to make a linux Xorg based os recognize or use multiple screens without a graphic card?

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